Lamination of thermoplastic polymers



Jan. 6, 1959 J. FlTZ HARRIS LAMINATION OF THERMOPLASTIC POLYMERS 6 Sheets-Sheet 1 Original Filed April 4. 1955 FIG.I

FIG. 2

INVENTOR. LEO J. FH'z Harris AJLfaA- ATTORNEYS Jan. 6, 1959 L. J. FITZ HARRIS LAMINATION OF THERMOPLASTIC POLYMERS Original Filed April 4. 1955 6 Sheets-Sheet 2 FIG. 3

FIG. 4

INVENTUR. LEO J- FH'Z Harris ATTORNEYS Jan. 6, 1959 J. Fl TZ HARRIS 2,867,241

LAMINATION OF THERMOPLASTIC POLYMERS Original Filed April 4. 1955 6 Sheets-Sheet 3 FIG. 5

FIG.6

INVENTOR. LEO J. Fitz Harris JAZM ATTORNEYS Jan. 6, 1959 J. FITZ HARRIS 2,857,241

LAMINATION OF THERMOPLASTIC POLYMERS Original Filed April 4, 1955 6 Sheets-Sheet 4 FIG.8

INI'ILYTOR. LEO J. FilzHclrriE ATTORNEYS Jan. 6, 1959 J, rrz HARRls 2,867,241

LAMINATION OF THERMOPLASTIC POLYMERS V Original Filed April 4, 1955 6 Sheets-Sheet 5 FIG. 9

|o NATURAL RUBBER FIGJ3 |4\ PHENOLFORMALDEHYDE RESIN INVENTOR. POLYTRIFLUOROCHLOROETHYLENE LEO FHzHOrri-s By Ajax! ATTORNEYS Jan. 6, 1959 n'z HARRIS 2,867,241

LAMINATION OF THERMOPLASTIC POLYMERS Original Filed April 4, 1955 6 Sheets-Sheet 6 FIG. I4

ALUMINUM EPOXIDE RESIN W l2 POLY TRIFLUOROCH LOROETHYLENE NEOPRENE OLYTRIFLUORO CHLOROETHYLENE INVENTOR. Leo J'. Fi-fz Harris ATTORNEYS United LAMINATION F THERMOPLASTIC POLYMERS Original application April 4, 1955, Serial No. 499,071. Divided and this application May 7, 1956, Serial No. 583,267

14 Claims. (Cl. 138-55) This invention relates to a novel thermoplastic polymer surface and the method of making it. This invention, in one of its aspects, relates to a process for fusing thermoplastic polymer particles to a thermoplastic polymer film. In another of its aspects this invention relates to the construction of useful end products by means of the novel polymer surface of this invention.

This application is a division of my prior and copending application Serial No. 499,071, filed April 4, 1955.

A wide variety of olefinic polymer are commercially available today. These polymers are used as protective coatings, electrical insulation, tank liners, etc. Representative of the better known olefinic polymers are polymers of ethylene, vinyl chloride, vinylidene chloride, and trifiuorochloroethylene. These olefinic polymers are fabricated into a variety of useful items by molding and other standard techniques. However, in many instances, for example in the preparation of laminates, the nonadhesive character of the olefinic polymers generally, and of the halogenated olefinic polymers in particular, has seriously limited the utility of the polymer. A number of techniques have been proposed for applying polymer surfaces to other surfaces. Thus, the polymer film has been bonded to fiberglass fabric which in turn is bonded to the other surface by means of a suitable adhesive. This technique involves the use of costly presses, long cycles and interrupted production, and is not always satisfactory. Certain of the olefinic polymers can be flame sprayed, e. g., polyethylene, but this is not advisable with the halogenated olefin polymers and particularly with the perfluorochloroolefin polymers, since they tend to decompose usually with the liberation of toxic fumes. Apart from the decomposition of the material, the bond strength of the polymer coating is not always adequate. Dispersion of polymer particles in suitable liquids have also been tried as a means of applying polymer coatings. However, this technique is obviously limited to use Where the surface to be coated is not deleteriously effected by the solvent used in the dispersion and where the coated object can be baked in a limited size oven. Additionally, such dispersions do not always produce the quality of coating which is desired.

It is an object of this invention to provide a thermoplastic halogenated olefin polymer surface which will facilitate the application of polymer surfaces to other materials.

It is another object of this invention to provide a technique for surfacing articles with thermoplastic polymers.

It is another object of this invention to provide a novel method for constructing thermoplastic polymer lined objects.

It is another object of this invention to provide a means for bonding thermoplastic polymers to other materials.

It is another object of this invention to provide a bondable surface on thermoplastic polymers. The term polymer, as used herein, includes both homopolymers and copolymers.

Various other objects and advantages of the present 2,867,241 Patented Jan. 6, 1959.

ice

invention will become apparent to those skilled in the art on reading the accompanying description and disclosure.

In general, the above objects are accomplished by interposing a plurality of thermoplastic polymer particles between a surface of a sheet or film of a thermoplastic polymer and a surface of a settable material to which the polymer is to be bonded, fusing the particles to the thermoplastic polymer and embedding them in the set table material. The settable material to which the polymer is to be bonded can additionally be bonded to a surface of another material, e. g., a metal surface. Thus, the particle provide a means for securing or anchoring a polymer film surface to other surfaces or materials. Fusion of the thermoplastic particles to the thermoplastic polymer surface is effected by heating the polymer and particles above the fusion point. The thermoplastic polymer with fused particles may be subjected to a variety of heat treating processes, e. g., quenching, to control physical properties, such as hardness, etc.

In order to illustrate the invention, reference should be had to the following detailed description and figures of the drawing in which:

Figures 1, 3, 5 and 7 are photographs of a homopolymer of trifiuorochloroethylene film to which was fused particles of a homopolymer of trifiuorochloroethylene in varying particle sizes as discussed in the examples. Magnification is about 1.5 times;

Figures 2, 4, 6 and 8 are cross-sectional views of Figures 1, 3, 5 and 7 respectively, in which the magnification is approximately 15 times;

Figure 9 is a cross-sectional view of a film of a homopolymer of trifiuorochloroethylene which is bonded to a layer of natural rubber by inter osed polymer particles which are fused to the polymer film and embedded in the natural rubber;

Figure 10 is a view along line l10 of Figure 9 showing the distribution of particles;

Figure 11 is a front view of a tank, constructed by the process of this invention, having a homopolymeric trifiuorochloroethylene lining and a supporting phenol formaldehyde exterior;

Figure 12 of the drawing is a top view of the tank of Figure 11;

Figure 13 is a cross-sectional view of the tank of Figure 11 taken along line 13-13 showing the bonding of the polymeric liner to the supporting phenolic exterior by means of the interposed layer of particles which are fused to the polymeric liner and embedded in the phenolic support;

Figure 14 is a cross-sectional view of a homopolymer of trifiuorochloroethylene bonded to an aluminum surface With an epoxide resin adhesive;

Figure 15 of the drawing is a cross-sectional view of a homopolymer of trifiuorochloroethylene bonded to a steel surface with a neoprene cement.

As indicated previously, any thermoplastic polymer, independent of its inherent adhesive characteristics, can be laminated by the process of this invention. Representative of such thermoplastic polymers, are the homopolymers and copolymers of ethylene, vinyl chloride, vinylidene chloride, vinyl acetate and trifiuorochloroethylene. While this invention is described with particular reference to the above described representative thermoplastic, it will be apparent that any fusible thermoplastic polymer can be employed. In this connection, it should be noted, that the polymer particles and polymer film, while they must be fusible, need not be of the same polymer family. For example, polyvinyl chloride can be fused to polyvinylidene chloride. However, in a preferred method of operation, identical polymer particles and film are employed since maximum bond strength is thus obtained.

Fusion of the polymer particles to the polymer film is accomplished by maintaining them in contact at fusion temperaturef'and in the absence of appreciable pressure for a period of time sutficient to permit fusion. Pressure shouldbe avoided, since otherwise the particles will tend to fuse.into the film to produce aheavier film. The fusion operation can be carried out in an oven, in which instance the film,.with particles distributed over its surface, is heated at the required temperature for the required period of time. The process can also be carried out in a continuous heating operation in which the thermoplastic polymer film travels on a continuous belt through an oven. The particles are distributed over a surface of the film prior to its passage into the oven. Thenecessary residence time is obtained by varying the speed at which the film moves and by using an oven of appropriate length. The oven can be heated by electricity, gas or any other convenient heating arrangement. Fusioncan also be accomplished by high frequency heating at the frequency. appropriate. for .fusing of the particular resin or polymer and bylocalized heating, for example with a hot iron.

Quantitative distribution of fused particles over the polymer film will vary depending upon the use for which the polymer film is intended. Where ahigh bond strength is required, the number of particles per unit .area is maintained at a relatively high level, whereas where low bond strength can be tolerated the number of particles per unit area can be maintained at a relatively low level, also areas where no bonding is desired or required can be kept free of anchoring particles of the polymer. Generally, from about to about 100 percent of the area of the thermoplastic film has particles fused to it and preferably to 90 percent of the area.

Control of the distribution of particles can be achieved in a variety of ways. Most molding powders and particularly polymeric trifiuorochloroethylene molding powders are available in low density and high density form. The low density powder is a powder of relatively high surface area per unit volume, whereas the high density molding powder has a relatively low surface area per unit volume. When heated to its softening temperature the low density molding powder is converted to ahigh density powder and contracts to a particle of considerably reduced size (usually about 6 its original size). The high density powder, on the other hand, does not decrease appreciably in size by heating. distribution of particles over the surfaceof the film can be controlled by use of either the low or the high density molding powder. For example, if the quantity of particles is to be kept reasonably low, a low density molding powder can be applied evenly over the surface so as to completely cover the surface of the film. On heating the low density powder, it contracts and separately fuses to the film leaving an appreciable area of free space. This same effect can be realized by controlled distribution of the high density molding powder. The variation in the surfaces which can be produced will become more apparent hereinbelow, in the examples and .in the.

figures of the drawings.

Representative of the settable materials to which thermoplastic polymers can be joined by means of the particulate surface of this invention, are the hydraulic polymers may be bonded to a considerable variety of The settable materials. The settable materials generally are liquid, liquefiable or otherwise distensible at the time they are contacted with the particulate surface so that the material can be forced between, over and around the particles and subsequently set into a relatively firm and substantially non-removable layer after contact has been established. The setting of the material can be accomplished by procedures which are standard with the material involved. For example, concrete, which sets by hydration, can be allowed to stand for the required period of time. Thermosetting resins set by heating at the required temperature, and also by the use of a cross-linking or curing agent which can be accelerated with heat. Where temperature is required, it should not, of course, be above the softening temperature of the polymer involved. In most instances, pressure is not required, although pressure can be employed provided that suitable precautions are taken to protect the polymer film from distortion, as for example by backing up the As indicated previously, a variety of particulate surfaces can be prepared. In selecting the particulate surface, one of the determining factors is the desired bond strength. Another determining factor is the material in which the particulate surface is to be embedded. Thus, where highly viscous mastic type cements, etc. are to be employed, the particles should not be too closely packed, since the cement may not adequately surround them. On the other hand, where the material in its precured state is relatively fluid, then tightly packed particles can be utilized. As indicated previously, the size anddistribution of the individual particles can be varied dependingupon the particular conditions encountered, that is dependent upon the thickness of the polymer sheet, the viscosity of the convertible resin and the desired bond strength. While particle size can be varied within relatively wide limits, the following tabulation is presented in order to illustrate preferable ranges of particle size depending on film thickness.

TABLE I Low Density Sheet Thick- Particle Size, ness, Inches Inches 0. 017-0. 031 005-. 010 0. 031-0. 063 010-. 015 0. 063-0. 094 015-. 025 094 and up 025 and up High Density Sheet Thick- Particle Size, ness, Inches Inches 005-. 010 005-. 010 010-. 020 010-. 015 (120-. 040 015-. 025 040 and up .025 and up In order to illustrate the preparation of the particulate surfaces of this invention, the-following examples are presented below.

Example I The homopolymer of trifluorochloroethylenc, N. S.- T. (no strength temperature) about 300 was covered with finely divided low density polymeric trifiuorochloroethylene molding powder. The entire surface of the polymer film was covered. The film and particles were placed in an oven where they were heated at a temperature of about 250 C. for about 30 minutes. The film was removed from the oven and quenched in cool water. The'nonfused or loosely bonded particles were removed from the film by scraping and are reusable. Figures 1 and'2 of 'the drawing show the particulate surface film thus produced. In Figure 1, the photograph was taken at a angle with a magnification of approximately 1.5 times. Figure 2 of the drawing was taken, using standard metallurgical techniques (i. e., a section of the film was cast in a Bakelite cylinder and polished). Magnification here was about 15 times.

Example II The process of Example I was repeated, except that larger particle size powder was used. Figure 3 presents a 90 angle view of the particulate surface on the film in which the magnification is approximately 1.5 times. Figure 4 is a cross-section of Figure 3 obtained by metallurgical techniques in which the magnification is approximately 15 times.

Example 111 Approximately equal parts of the small and the large particle size powders used in Examples I and II respectively, were admixed. The admixed particles were evenly distributed over a film of a homopolymer of trifiuorochloroethylene, such as used in Examples I and II. The film and particles were then heated in an oven at 250 C. for approximately 30 minutes after which non-fused particles were removed by scraping. Figure 5 is a photograph taken at approximately 90 angle of the particulate surface thus produced. Magnification is approximately 1.5 times. Figure 6 is a cross-section of Figure 5 obtained by metallurgical technique in which the magnification is approximately 15 times.

Example IV As indicated previously, a variety of surfaces can be prepared. In the preceding examples a low density mold ing powder was used which contracted on heating, leaving free spaces around the individual particles. This example, Figure 7 illustrates the preparation of a fine-grained porous particulate surface. In this example finely divided (about 200 mesh) high density polymeric trifiuorochloroethylene molding powder was evenly distributed over a surface of a film of a homopolymer of trifiuorochloroethylene. The film and particles were heated at a temperature of about 250 for approximately 30 minutes after which unfused particles were removed by scraping and the resulting product quenched in cool water. Figure 7 is a photograph taken at a 90 angle to the particulate surface. Magnification is about 1.5 times. Figure 8 is a cross-sectional view of Figure 7 obtained by metallurgical techniques. Magnification is approximately 15 times. In this example, the individual particles of the polymer are fused to the polymer film and to surrounding polymer particles. A porous fine-grained surface was produced by this technique.

The above examples illustrate the preparation of a particulate surface on a surface of a homopolymer of trifluorochloroethylene. By employing substantially identical techniques with appropriate modification of fusion temperature, substantially similar surfaces can be developed on other thermoplastic polymer films. The following examples illustrate this point.

Example V A film of a homopolymer of ethylene is covered with homopolymeric ethylene molding powder. The polymer film and particles are then heated in an oven maintained at a temperature of about 115 C. for about 10 minutes after which the film together with fused particles is removed, and scraped, to remove loose particles. The surfaces obtained with the polyethylene material are similar to the surfaces shown photographically in Figures 1, 3, 5 and 7. Since polyethylene is not available in low density form, distribution of the particles is controlled mechanically.

Example VI A film of a polymer of vinylidene chloride'is covered with particles of a polymer of vinylidene chloride. The film and particles are then heated at a temperature of 6 about 185 C. for about 15 minutes after which the film with fused particles is removed, scraped and quenched. Surfaces corresponding to the surfaces portrayed in Figures 1, 3, 5 and 7 are obtained by selection of the particle size and by distribution of the particles over the film surface.

Example VII A film of a polymer of vinyl chloride is covered with particles of a polymer of vinyl chloride. The film and particles are then heated at their fusion temperature about 175 C. for about 15 minutes, after which the film with fused particles is removed, scraped and quenched. Surfaces corresponding to. the surfaces portrayed in Figures 1, 3, 5 and 7 are obtained by selection of the particle size and by distribution of the particles over the film surface.

Example VIII A film of a copolymer of vinyl chloride and vinyl acetate is covered with particles of a polymer of vinyl chloride and vinyl acetate. The film and particles are then heated at a temperature of about C. for about 15 minutes after which the film with fused particles is removed, scraped and quenched. Surfaces corresponding to the surfaces portrayed in Figures 1, 3, 5 and 7 are obtained by selection of the particle size and by distribution of the particles over the film surface.

After the particulate surface has been prepared, as described above, it can then be bonded to a considerable number of materials. As indicated previously, the materials to which the particulate surface can be bonded are characterized, in that they are all settable or convertible. These settable or convertible. materials are distensible, i. e., liquid, liquefiable or otherwise capable of being forced between, around and over the particles under the conditions of application, and subsequently set or converted to a relatively non-distensible, non-liquid and non-flowable material. The use of the particulate surfaces of this invention in the fabrication of a number of end items is described in the examples below.

Example IX Finely divided (about 200 mesh) high density homopolymeric trifluorochloroethylene molding powder, was evenly distributed over a surface of a film of a homopolymer of trifiuorochloroethylene. The film and particles were heated at a temperature of about 250 C. for approximately 30 minutes after which unfused particles were removed by scraping. The resulting product was quenched in cool water. The particulate surface of this example is illustrated photographically in Figures 7 and 8 and diagrammatically in Figure 10 of the drawing. The particulate surface thus produced, was embedded in a sheet of uncured 50 durometer natural rubber approximately 0.5 inch thick. The rubber was cured for 20 minute sat approximately C. The rubber was firmly bonded to the polytrifluorochloroethylene film which formed a protective surface for the rubber. The resulting product is illustrated diagrammatically in Figure 9 of the drawing in which reference numeral 10 indicates the natural rubber component, reference numeral 11 indicates the particles which are fused to the polymer surface and reference numeral 12 indicates the polymer surface of po1ytrifluorochloroethylene. Figure 10 is a view of the particulate surface and Figure 9 is taken along line 10-10. Bonding of the rubber layer to other surfaces, such as steel, can be accomplished using rubber cement. In this connection, it should be noted that the intermediate rubber layer affords protection to the polymer film since the rubber layer is resilient and will absorb shock, as contrasted with the relativelyhard and brittle intermediate layer obtained by the use of most thermo-setting resins, as for example, the epoxide resins. The use of rubber as a bonding layer will in'many instances be advantageous because of this property.

i in Example III.

bedded in Portland cement. 'set, after which the polymer film could not be removed Example X {A'homopolymer of trifiuorochloroethylene, N. S. T. about 300 was covered with finely divided low density polymeric trifiuorochloroethylene molding powder. The film and particles were placed in an oven and heated for about 30 minutes at a temperature of about 500 F. The film was removed from the oven and quenched in cool water. The particulate surface thus prepared is illustrated with an aluminum panel after which the assembly was cured by heating for approximately 30 minutes at 115 C. A protective sheet or coating of polytrifiuorochloroethylene was thus firmly bonded to the aluminum panel.

This structure is shown diagrammatically in Figure 14 r of the drawing in which reference numeral 18 is the aluminum panel, reference numeral 19 is the epoxide resin, reference numeral 11 represents the polymer particles and reference numeral 12 is the polytrifluorochloroethylene film.

Example XI Example Xll A particulate surface was prepared on a homopolymer i of trifiuorochloroethylene as described in Example II and as shown photographically in Figures 3 and 4 of the drawing. The particulate surface was coated with a GR- S based cement (a copolymer of butadiene and styrene marketed by Minnesota Mining and Manufacturing as i 7 EC524). at room temperature and while still tacky the rubber cement was placed in contact with a steel panel. The

cement was given a gentle cure of 65 C. for minutes. The polytrifluorochloroethylene polymer surface was firmly bonded to the steel panel. This structure is shown diagrammatically in Figure 15 of the drawing in which reference numeral 20 indicates the steel surface, reference numeral 21 indicates the neoprene cement, reference numeral 15 indicates the particulate surface of the polymer and reference numeral 14 indicates the polymer film.

Example XIII v i A particulate surface was prepared on a homopolymer of trifiuorochloroethylene corresponding to that described The particulate surface was then em- The cement was allowed to without destruction of the film. The use of the particulate surface of this invention in bonding polymer sheets and films to hydraulic cements is considered to be valuable in industrial plants where a spillage of corrosive chemicals is anticipated. Chemically resistant thermoplastic polymers, such as the homopolymer of trifiuorochloroethylene, can be fabricated into standard sized floor tiles, applied, and be set into the concrete flooring. The par- .ticulate surface can also be applied as a protective poly- .mer layer on plaster walls, etc.-

' Example XIV f 11 A'particulate surface was preparedon a homopolymer 'of'trifluorochloroethylene corresponding to that described in Example III and shown photographicallyv in Figures 5 and 6. The particulate surface was coated with neo- Most of the solvent was allowed to evaporate prene based cement (Minnesota Mining and'Manufacturing EC-880). 'Most of the solvent was permitted to evaporate at room temperature. While still tacky, the neoprene cement was placed in contact with a steel panel. The assembly was heated at F. for approximately /2 hour. The polytrifluorochloroethylene polymer film was firmly bonded to the steel panel, this product is illustrated diagrammatically in Figure 15 of the drawing in which reference numeral 11 represents the intermediate layer of neoprene.

Example XV Laminated structure similar to that described in Example IX, are prepared using silicon rubber, Hevea rubber and butyl rubber withappropriate adjustment of curing time and temperature for the particular rubber employed.

Example XVI Employing the procedure of the preceding Examples IX-XV, the particulate surface of the polyethylene of Example V, polyvinylidene chloride of Example VII and the polyvinyl chloride-vinyl acetate copolymer of Example VIII is used to obtain laminates corresponding to the polytrifluorochloroethylene laminates previously dedescribed.

As indicated previously, a considerable variety of end products can be prepared using the particulate surface of this invention. The foregoing examples illustrate the preparation of laminates in the form of coatings. The following examples are intended to show the use of the particulate surface of this invention in the preparation of vessels, pipes, etc. This example illustrates the construction of a tank.

Example XVII A film of a homopolymer of trifiuorochloroethylene.

(approximately 5 mils thick) is formed into a cylindrical shape, closed at one end. Particles of a homopolymer of trifiuorochloroethylene are fused to the outer surface of the film by heating, as described in Example I. Uncured phenol formaldehyde resin in liquid form is applied evenly over the particulate surface of the polymer by spraying until a thickness of about 25 mils is reached. The phenol formaldehyde resin is then cured by heating at about 275 F. The cured phenol resin is firmly bonded to the polymeric lining. cylinder is prepared as described above. A gasket of polytrifluorochloroethylene, preferably the elastomeric copolymer of trifiuorochloroethylene and vinylidene fluoride in a 50/50 mole ratio, is then prepared with a circumference corresponding to the circumference of the open ends of the two cylinders. The gasket is used to provide a cushion between the flanges and to take up irregularities, the gasket can be omitted when the tank is not subject to shock, etc. The open ends of the two cylinders are then brought into contact with the intervening gasket. Holes are drilled through the flange and bolts are insertedso as to clamp the two cylinders together. A rigid tank (capacity about 30 gallons) suitable for storage of corrosive chemicals is thus produced. This tank is illustrated in Figures 11, 12 and 13 of the drawings in which Figure 11 is a front view, and Figure 12 is a top view, Figure 13 is a cross-sectional view taken along line 13-13. Referring to the figures of the drawings, reference numeral 14 represents the inner layer of the homopolymer oftrifiuorochloroethylene, refence numeral 15 represents the particles of polymeric A second plastic polymer. The following examples illustrates the fabrication of a plastic lined pipe.

Example XVIII An extruded tube of a homopolymer of trifluorochloroethylene is heated in contact with particles of polymeric trifiuorochloroethylene substantially as described in Example I. During the heating operation, the tube which is of approximately 1 inch inside diameter is supported on a steel mandrel. After the particles have been fused to the outer surface of the tube, the tube is covered with an epoxide resin (a condensation product of bisphenol and epichlorohydrin available commercially as Epon 828). The resin contains approximately 14 weight percent of metaphenylene diamine curing agent. The resin is cured by heating at approximately 60 C. for approximately 60 minutes. A chemically resistant plastic lined pipe having excellent impact resistance is thus produced.

Where flexibility is an important feature of the vessels which can be fabricated by the process of this invention, then elastomeric materials, such as natural rubber, neoprene, etc., can be substituted for the relatively hard thermo-setting resins. used in Examples XVII and XVIII. The following example illustrates the preparation of a flexible lined pipe.

Example XIX An extruded tube (5 mils wall thickness) of a homopolymer of trifluorochloroethylene is prepared with a particulate surface corresponding to that described in Example XVIII. The tube with particles fused to its outer surface, is supported on a steel mandrel and is wrapped with uncured 50 durometer natural rubber, approximately 0.06" thick. In wrapping with the rubber, sufficient pressure is used to embed the particles in the inner layer of the rubber sheet by stretching the rubber sheet as it is applied. The tube is wrapped until an outer rubber layer approximately 0.12" thick is obtained. The rubber is then cured by heating at approximately 160 C. for about 0.5 hour. The rubber is firmly bonded to the inner polytrifluorochloroethylene protective liner and acts as a resilient and flexible support for the liner. While natural rubber is used in this example, other elastomeric materials can be substituted to meet the requirements of the particular application. For example, where oil-resistance is required of the flexible rubber supporting exterior layer, neoprene can be employed. In constructing these resilient pipes, the outer rubber layer can also be applied from cements and by other convenient techniques.

Various alterations and modifications of the invention and its aspects may become apparent to those skilled in the art without departing from the scope of this invention.

Having thus described my invention, I claim:

1. A novel pipe which comprises an inner protective layer of a thermoplastic olefin polymer film, an outer supporting layer of a settable material and interposed between said inner protective layer and said outer supporting layer, a plurality of thermoplastic olefin polymer particles, said particles being fused to a surface of said protective layer, and embedded in a surface of said supporting layer.

2. The pipe of claim 1 in which the settable material is a thermo-setting resin.

3. The pipe of claim 2 in which the thermosetting resin is an epoxide resin.

4. The pipe of claim 2 in which the thermosetting resin is a phenol formaldehyde resin.

5. The pipe of claim 1 in which the settable material is an elastomer.

6. The pipe of claim 5 in which the elastomer is neoprene.

7. The pipe of claim 5 in which the elastomer is natural rubber.

8. The pipe of claim 1 in which the polymer film is a polymer of trifiuorochloroethylene.

9. The pipe of claim 1 in which the polymer film is a polymer of vinyl chloride.

10. The pipe of claim 1 in which the polymer film is a polymer of ethylene.

11. The pipe of claim 1 in which the polymer film is a polymer of vinylidene chloride.

12. A novel pipe which comprises an inner protective layer of a thermoplastic trifluorochloroethylene polymer film an outer supporting layer of a rigid phenol formaldehyde resin and interposed between said protective polymer film and said supporting resin, a plurality of trifluorochloroethylene polymer particles, said particles being fused to a surface of said protective polymer film and embedded in a surface of said supporting resin.

13. A novel flexible pipe which comprises an inner protective layer of a trifluorochloroethylene polymer film an outer supporting layer of natural rubber, and interposed between said protective polymer layer and said supporting rubber layer a plurality of trifluorochloroethylene polymer particles, said particles being fused to a surface of said protective polymer layer and embedded in a surface of said supporting layer.

14. A process for fabricating a plastic lined pipe which comprises providing an inner protective layer of a thermoplastic olefin polymer in tubular form, fusing particles of a thermoplastic olefin polymer to the outer surface of said tubular thermoplastic olefin polymer, applying a settable material to the 'outer surface of said tubular thermoplastic olefin polymer and embedding said particles in said settable material.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A NOVEL PIPE WHICH COMPRISES AN INNER PROTECTIVE LAYER OF A THERMOPLASTIC OLEFIN POLYMER FILM, AN OUTER SUPPORTING LAYER OF A SETTABLE MATERIAL AND INTERPOSED BETWEEN SAID INNER PROTECTIVE LAYER AND SAID OUTER SUPPORTING LAYER, A PLURALITY OF THERMOPLASTIC OLEFIN POLYMER PARTICLES, SAID PARTICLES BEING FUSED TO A SURFACE OF SAID PROTECTIVE LAYER, AND EMBEDDED IN A SURFACE OF SAID SUPPORTING LAYER.
 14. A PROCESS FOR FABRICATING A PLASTIC LINED PIPE WHICH COMPRISES PROVIDING AN INNER PROTECTIVE LAYER OF A THERMOPLASTIC OLEFIN POLYMER IN TUBULAR FORM, FUSING PARTICLES OF A THERMOPLASTIC OLEFIN POLYMER TO THE OUTER SURFACE OF SAID TUBULAR THERMOPLASTIC OLEFIN POLYMER, APPLYING A SETTABLE MATERIAL TO THE OUTER SURFACE OF SAID TUBULAR THERMOPLASTIC OLEFIN POLYMER AND EMBEDDING SAID PARTICLES IN SAID SETTABLE MATERIAL. 